Fluid-actuated servomotor control valve system



G. T. RANDOL April 15, 1952 FLUID ACTUATED SERVOMOTOR CONTROL VALVE SYSTEM 3 SheetsSheet l Filed June 9, 1947 w T 9 N Md M R T 05 "T @w I 6 A TOR/V5 Y...

April 15, 1952 c. T. RANDOL 2,592,600

FLUID-ACTUATED SERVOMOTOR CONTROL VALVE SYSTEM Filed June 9, 1947 5 Sheets-Sheet 2 INVENTORS ilhi. 6 Glenn T. Randal, 2w; ,1, /0 BY my EFT-E- Ai fi April 15, 1952 RANDOL 2,592,600

FLUID-ACTUATED SERVOMOTOR CONTROL VALVE SYSTEM Filed June 9, 1947 5 Sheets-Sheet. 3

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- INVENTOR: G/e-nn 7i Randal,

Patented Apr. 15, 1952 UNITED STATES PATENT OFFICE FLUID-ACTUATED SERVOMOTOR CONTROL VALVE SYSTEM 19 Claims.

This invention relates to control valve systems for fluid-actuated servomotors, and more particularly to control valving for causing the movable element of a fluid pressure actuated servomotor to move from one position to another and automatically reverse itself and return to its initial position, all under the action of differential or motive fluid pressure.

One of the primary objects of my invention is to produce an improved reversing valve mechanism for use in controlling the movement of the movable element of a fluid-actuated servomotor from one position to another and return.

Another salient object is the provision of an improved reversing valve means and control means therefor which is capable of so controlling the movable element of an associated fluid motor power means, that a one-way stroke of the movable element can be obtained, followed by a two- Way stroke and vice versa, depending upon certain conditions.

A further important object is to provide an improved reversing valve means and control means therefor for association with a fluid servomotor whereby controlled automatic reversing movement of the element of the servomotor can be prevented, notwithstanding the reversing valve means has been set to cause the movable element to reverse automatically.

Another important object of the invention is to associate with a fluid servomotor an improved reversing valve means and controls therefor whereby, under certain conditions, a single movement of the servomotor movable element will result, while under other conditions a reciprocable movement of said element will result.

A further object is to produce areversing valve means for association with a piston-type servomotor which can be controlled by a speed-responsive device.

A still further object is to provide a reversing valve means for association with a fluid servomotor and so control said valve means by a personally-operable member that themovable element of the servomotor can, under the action of dilferential fluid pressure, be caused to move from one position to another and automatically return to the initial position and following said functioning the valve means can be reset so that the cycle can be repeated at will.

A further object is to produce an improved reversing valve mechanism and control means therefor.

Another object is to so associate with a reversing valve means improved shut-off valve means and control means for both valve means whereby the movable element of a fluid servo motor can be caused to move in one direction, to have a return movement or to have a reciprocable movement.

A further object is to provide improved means for resetting a reversing valve means so that it can again function to cause an element controlled thereby to have a reciprocable movement.

A more specific object is to provide a control means embodying a reversing valve means for a fluid servomotor which is particularly adaptable for controlling the changing of speed drives of a motor vehicle.

Other objects of the invention will become apparent from the following description taken in connection with the accompanying drawings in which:

Figure 1 is a schematic view with parts in section of a control system embodying my invention and showing a fluid servomotor, together with an associated reversing valve means and a combined personally-operable and speed-responsive control means therefor, the reversing valve means being shown in the position assumed when the personally-operable means is in its released position, the speed-responsive means is inactive to close the primary circuit and the fluid motor piston is about to complete its movement to the upper end of the cylinder remote from its normal initial position, and wherein the electrical circuits are depicted in solid and broken lines to indicate energized and non-energized conditions thereof respectively;

Figure 2 is a top view of the reversing valve means and fluid servomotor as shown in Figure 1;

Figure 3 is an end view of the reversing valve means, said view being taken on the line 3 3 of Figure 2;

Figure 4 is a vertical sectional view of the reversing valve means taken on the line 4-4 of Figure 3 and showing the parts in the position assumed when the fluid servomotor piston is in the position shown in full lines in Figure 1;

Figure 5 is a sectional view of the upper part of the reversing valve means and showing how the reversing valve element is shifted from one of its operative positions to the other by the fluid motor piston as the piston moves from its full line position shown in Figure 1 to its dashed line position at the upper end of the cylinder where its stroke is completed;

Figure 6 is a schematic view of the speed-re- 3 sponsive'means showing the position it assumes to open the primary circuit and close the secondary circuit, and wherein said circuits are depicted energized and de-energized by solid and dashed lines respectively;

Figure 7 is a vertical sectional view of the reversing valve means similar to that of Figure 4, but showing the parts in the position wherein the reversing valve element has been shifted by the piston of the servomotor when it reaches the upper end of its cylinder and the solenoid controlled shut-off valve element is closed to prevent return movement of thepiston;

Figure 8 is another vertical sectional view-oi the reversing valve means showing the parts in the position assumed when the "reversing valve element is reset after the piston ,of :the fluid servomotor has been caused to return toits initial position at the bottom ,of its cylinder;

Figures 9 and 10 are-sectional views taken on the lines -9-9 and J 0, respeotively of :Figure 4 showing details of the master switch embodied in the: reversing valve means; and

-Figure 11 is'a side view, partly in section, of a modified reversing valve means wherein the 'manual control is mechanically connected to reset the reversing valve element and open 'the shut-01f :valve element.

' Referring to=the-drawings in detailandfirstto Figure 1, there is disclosed by way of example, a control system for -a double actingservomotor or power cylinderof the pneumatic-type in which i iembodieda reversing "valve means and other associated means for con-trollingtheservomotor. ,I he fluid motor is generally indicated =by'the letterF and is shown, bywayof example only, as one type of motor which can'be controlled-by 'the reversing valve means. This particular servomotorisof the piston and cylinder type-but ,it is obvious that other forms of servomotor, such as the diaphragm type, can be controlled. Th p wer for operating the illustrated servomotor .F is a source of .difierential fluid pressure andin ,theparticular system disclosed-this source rissubeatmosphericair pressureor suction. It is .also contemplated that the control systemcan .beassociated with a servomotor whichis adapted to be actuated by .air or liquid under super- ,atmospheric pressure.

In ,Eigure ,1 the .source of sub-atmospheric pressure isiindica'ted vby the tank 51 which can .be connected to suction means. The reversing valve lmeansof the control system is indicated generally by the letters RV and associated-with this valve .means ,is a shut-01f valve SV, Also shown as part ofthe control system is a speedresponsive device S, a control valve CV interposed between the tank T and the reversing 'valve means, and a manual orpersonally-operablecontrol element'in theiormof a pedal P-which is arranged to control a diaphragm motorD where- .bythe resetting of the reversing valve means can be accomplished. Theparticular control system 'disclosedi'in Figure =1,by way of example, is inorpersonally-operable=Pwould be the accelerator pedalwhich is employed-to vary the speedofthe engine of the motor vehicle, the speed-responsive device S would be responsiveto thespeedof the vehicle and tank T would be connected to the I suction -or inlet manifold of the vehicle engine.

Numerous other uses of the control system for a servomotor appear obvious and it is not intended that the invention in any way be limited by the particular mechanism which the whole system, including the servomotor, is to be associated.

The servomotor F, as shown in Figure 1, has a cylinder 1 having mounted therein a reciprocablepiston element 2. One closed end of the cylinder is pivoted by a ipin 3 lto =.a bracket 4 mounted on a suitable support-'5. The-piston rod 6 of the servomotor extends out of the other closed end of the cylinder and is arranged to be connected to one arm 1 of a bell crank lever B, the other arm 9 of which is arranged to control the reversing valve means RV as will become apparent. The bell crank lever B has a pivot pin [0130 which it is rigidly secured, this pivot pin being mounted in an extension II on the cover12 of the casing 13 of the reversing valve RV, which casing in turn is bolted by a suitable bracket Id-to a support 15. :Inorderthat ithe piston may actuateany suitablemechanism, such as a change-speed transmission and also :a

vehicle clutch-mechanism ifdesired, the pivot pin It for the bell crank lever has secured thereto an arm '16 and connected to this arm is a :rod

H leading to mechanism -to be actuated. In event the mechanism to be actuated is 'a vehicle clutch, such will be provided with arrengaging spring-against the bias of which theclutch will be disengaged. For purposesof this disclosure, such a spring is indicated at H so that it-will be apparent how it will be efiectiveon the servomotor. The spring'could also beany-otherspring reversing valve means RV and the reversing valve means is in turn connected to the-servo- .cylinder 'L-it'being noted'in-Figure 1 that aconduit 2-0 leads from 'the reversing valve means to 'theupper end of the cylinder of the servomotor, ,and a conduit 32 leads fromthe reversing valve means -to the lower 'end of the servomotor. The diaphragmmotor -D associated with the reversing valvemeans and employedffor controlling the resetting "of the reversing-valve -element-is also connected to thetank T by aconduit '22, which conduit is arranged to be controlled by a valve DV interposed between the diaphragmmotor-and the-conduit 22. ThevalveDV isa-rrangedto be manually-controlled-by the pedal -P, or-equivalent personally-operable member, in a-manner which will be later described. a

The shut-01f valve SV, which 'is'associated "with the reversing valve means, is controlled by a solenoid 23 and this solenoid; "together with the solenoid '24 of the control valve-CV, are anranged -to be connected in-circuitsunderthe control of the speed-responsive device S anda master switch generally indicated by and -em bodied in the reversing valve means forcontrol purposes. As shown in the wiring diagramof Figure 1, 'the source of electricity is a battery B having one-terminal grounded and its other :ter-

minal connected by a conductor to a terminal 26 (Figure 10) of the master switch M. The other terminal 2'! of this master switch is connected by a conductor 28 to a terminal 29 of the solenoid 24 for controlling the valve CV. The other terminal 30 of the solenoid 24 is connected by a conductor 3| to parallel conductors 32 and 33. The conductor 33 is arranged to be connected to one terminal 34 of the solenoid 23 for controlling the shut-off valve SV. The other terminal 35 (Figure 3) of the solenoid 23 is connected by a conductor 35 to a primary contact 31 associated with the speed-responsive device S. Also associated with the speed-responsive device is a secondary contact 38 to which the previously referred to parallel conductor 32 is connected. Also associated with the speed responsive device is a common contact 39 which is grounded through a conductor 45.

The speed-responsive devices, as shown somewhat schematically in both Figures 1 and 6, has a movable switch member 4|, slidable on a shaft 42, which shaft is journaled at its opposite ends in suitable supports 43 and 44 and arranged to be driven by a suitable gearing 45 from any driving mechanism; such as, for example, the driving wheels of a motor vehicle. The shaft 42 of the speed-responsive device has pivoted centrifuge members 45 and 47 which are connected by links 48 and 49 to the movable switch member 4| by means of a sleeve 50. A calibrated spring 5| normally holds the centrifuge members in their inner position, as shown in Figure 1, when the speed-responsive device is at rest or substantially so, that is, the rotation of the shaft 42 is not effective on the centrifuge members. When the centrifuge members are substantially at rest the movable switch member 4| will be in its upper position so as to connect the primary terminal 31 with the grounded terminal 39 and thus complete a circuit through both the solenoids 23 and 24 to energize these solenoids, provided, of course, the master switch M is closed. This circuit will be referred to as the primary circuit. When the shaft 42 is rotated sufficiently the centrifuge members will be thrown outwardly in the manner indicated in Figure 6 and thus the switch member 4| will be moved downwardly" to thereby open the previously referred to primary circuit through the solenoids 23 and 24 and engage the secondary contact 38 to thus close a secondary circuit which will result in only the solenoid 24 of the control valve CV being energized, provided, of course, the master switch M is closed. It is thus seen that with the speed-responsive device controlling the primary and secondary circuits, then when the primary circuit is energized, as shown in Figure 1, both solenoids 23 and 24 of the valves SV and CV will be energized. When the solenoid 23 of the valve SV is energized, it will be in closed condition (Figures 4 and 7) and when the solenoid 24 of the valve CV is energized this valve will be in open position so that the reversing valve means will be connected to the source of sub-atmospheric pressure; that is, the disclosed tank T. The primary circuit is from the battery B through the conductor 25, the master switch M, conductor 28, the solenoid 24, conductors 3| and 33, solenoid 23, conductor 36 and back to ground by way of the primary terminal 31, movable switch member 4|, terminal 39 and conductor 40. The secondary circuit is from battery B through conductor 25, master switch M, conductor 28, solenoid 24, conductors 3| and 32 and back toground through the switch member 4| so as to connect the secondary terminal 38 of the speed-responsive device with the terminal .39 and grounded conductor 40, all as indicated in Figure 6. If desired, a manual switch 52 can beplaced in the conductor 25. This switch can be the ignition switch of a motor vehicle if the control system is to be associated with such.

The control valve CV may be any type of shutoff valve which, when open, will connect the conduits l8 and I9 and when closed will prevent the conduit H! from the tank T from communicating with the conduit l9 and connect the conduit IS with atmosphere. As shown in Figure 1, the illustrated control valve CV has a casing 53 divided into compartments 54 and 55 by a ported partition 56 with which is associated a valve seat 51. The compartment 54 is connected to the conduit l8 and the compartment 55 is connected with the conduit l9. Associated with the valve seat 51 is a movable valve element 58 positioned in the compartment 55 and mounted on the end of the stem 59 of the reciprocable solenoid armature which is carried within the valve casing 53. Besides cooperating with the valve seat 51, the valve element 58 is. also arranged to engage a valve seat 60 associated with a ported partition 6| positioned between the compartment 55 and the solenoid 24. The port in the partition leads to an air chamber 60 connected to atmosphere by a vent 60". The stem 59 of the solenoid is arranged to'be biased by a spring 62 so that the valve element will be caused to engage the seat 51 and be disengaged from seat 60 when the solenoid is deenergized and thereby prevent communication between conduits I8 and I9. Under such closed condition of the valve CV the conduit l9 will be in communication with the atmosphere, since the valve element 58 is free of seat 60. When the solenoid is energized the valve element 58 will be disengaged from seat 51 and engaged with seat 65, thus placing the conduits l8 and H! in communication with each other and preventing any communication thereof with atmosphere.

Referring to the details of the reversing valve means RV, the shut-off valve SV and the resetting means comprising the diaphragm motor D and its control valve DV, reference is now had to Figures 2, 3, 4, 5, and 7 to 10. The previously mentioned casing |3 for the reversing valve means RV is provided with a bore 63 at its upper end, which bore is closed by the cover l2 to which the bell crank lever 8 is pivoted. The central part of this bore has press-fitted therein a sleeve 64 in which is reciprocal the reversing valve element 65 of the spool type having an annular chamber 66 formed by the flanged ends 61 and 68. The bore 53 above the valve sleeve is in constant communication with the atmosphere through a plurality of ports 69 which are protected from entry of foreign material by a semicylindrical guard 10 formed as a flange on the gasket 1| between the cover I 2 and the casing. In order that the portion of the bore below the valve element may also be in constant communication with the atmosphere, the valve element has an axial passage 12 which communicates with ports 13 at the upper end of the valve. Thus the axial passage will be in communication with the previously mentioned atmospheric ports 69 in the valve casing.

The reversing valve element 55 has two servomotor operative positions, the upper of which is for connecting the upper end of the servomotor with a source of suction as tank T and 7 the lower of which is to connect the lower end of 'the servomotor withthe said source ofsuction. The upper position is shown in Figures 4 -an'd-8-andthe lower position in Figure '7. The annular-chamber B6 of the valve element is arranged to communicate in both of its positions with the conduit ['9 already referred "to and which-leads to-thetank Tby wayof the control valve V. This is accomplished by a passage "T4 -which extends through the valve casing and the-valve sleeve. in order to'connect' the chamber 'BB to the conduit 2 0 leading to the "upper end of "theservomotor F,'there'is providedinthe valve sle'eve and the valve cas'ing a passage -'communicating with the conduit 20. 'I-his pa'ssa'ge 15 is slightly above the passage T4 -so that when the valve element is in its upper position shown in Figures 4 and 8 there will be direct communication by way ofthe annular chamber 56 i in the valve element and the upper 'end of thes'ervomotor to the conduit I9 leading to {the tank through the control valve 0V. When Tthe valve element E5 is in 1 its lower position, .asshoWn inFi'gure'T, the annular chamber '66 will be caused to be in communication v :with e passage '16, a longitudinally extending passage 1'! in the ='casing wall and by means of 1 an angular passage I8 and a passage 78' extending-to the outside of the valve casing in communication with the ;previously referred to conduit 2 I leadingtothe lowerend-of the servomotor. When the valve element is in the .position shown in Figure 7 to make the connection with the lower end of the servomotor and the conduit 19 leading to the tank T, the

7 'lower'endofthe'servomotor will also be in communication with atmosphere byway of the' ports 69. If the valve CV is closed, then of course, irrespective of theposition'of the reversing valve element Giboth'ends of the s'ervomotor can be in communication with atmosphere for "conduit 9 -'cemmunicates with atmosphere through "air icha'mber fill "and vent ED -of *valve 'CV.

"The reversing valve element 65 is arranged to beLmoved to its upper position shown in Figures -4'5and'8 throughia spring Wand other apparatus to be :described. As already noted, the valve element, when'in its upper position, will be in a position to connect the upper end of the servo- :motor to the tank -'I and thus ii the control valve CV is open, suction will cause the piston :Zof the servomoto'r to be moved upwardly 'to the iupp'er1end of the cylinder, thus making a stroke which :is brought about by the differential actionof fluid pressure acting on oppositeside's of the eservo-pisto'n. In order that the reverszi-ng "valve element '65 can, under certain con- :ditions, be automatically shifted to its lower position as shown in Figure? so as to'oause a re turn movement of the piston 101 the 'servomotor from the upper end to its lower-end, :provision is made to shift the :reversing valve element by means of the already referred to arm 9 of the bell crank lever 1 which is actuateuty the servo-piston. v I

The valve element 65 has connected thereto cooperating with a longitudinalslot -82 in the surface of the-rod' 8ll. The upper en'cl of 'the. rod

8!] is arranged to be engaged by the a'rm 9 =just before the piston of the servomotor reaches its extreme'upper'end. From this "point to the end of the stroke of the piston thearm 9 "willact 'upon the rod8'll andshift the valve element-from the upper position'shown in Figures 4 and 8 the lowe'r position shown in Figured. 'A' sprin c, pressed ball detent 83 is also-carried by the cove'r and such cooperates with two-recesses and 85 for yieldably holding the valve element in'its two servo-operative positions. V

It is highly desirable when-thereve'rsing valve element 65 is'to beshifted from its upper position to its lower position that this shifting-take place very quickly so that the connections with the opposite ends of the servomotor will be quickly reversed. The rod 8!! has provided therein a plunger 86 backed by a'spring 81wlii'h is preloaded. The plunger has a reduced portion extending out of the rod' and such portion will be first engaged by the arm 9 as the piston 2 of the servomotor, during its upward stroke, reaches the point shown in solid lines in Figure 1. Continued-downward movement-6f the arm 9 as the piston continues its moveme rit to the extreme upper end of the cylinder "will result in the spring -81 being'additionally-compressed to increase its pre-lo'aded tension. By the additional tensioning of the spring '8'ljhowever, there will not be such a force oreated'as will overcome the resistance offered bythe hall detent B3 engaged in recess so that the rod '80 will be moved. 'However, when the arm =9 reaches a point in its downward {movement wherein it initially engages the rod 80, the ball detent83 will be urgedout of "the recess as shown in Figure 5. When the detent is mitdf the recess the compressed spring'8'1'will thenex pand and-be effective-to apply such aforcetoth'e rod '80 as to snap the'reversing valve'element "65 from its upper position to its lower position and thereby automaticallyreverse the 'fltiidfconduit connections "to the servomotor "so "that sub-'- atmospheric pressurewill 'be effective on the lower side of the pisto'nand atmospheriepressure on the upper side of the piston. Thus it is seen that the movement of the arm 9 asth'e piston of the servom'otor "approaches its "extreme upper position initiates the downward movement of the reversing valve element a'n'd the spring 8'! completes the movement ,di the valve element to its-lower position.

With" the reversing valve element 65, just described and its manner of shifting'inrespohse to the movement of the piston of the servomotor, it will be seen thatwith the valve element in its upper position it will be :possible to connect the upper end of the servomotor to the tank I and the lower end of the servomotor to atmosphere, and thereby cause the pistoni "of the servomotor to move from the lower end of its cylinder to the upper end; When the upperr'end -is reached the valve element will be automatically :shifted from its upper position to its lower positi0n,= as

shown inFigure 7, thus reversing the fiuidhonnections of the servomotor so that the upper *end will 'be connected toatmosphere "and the flower end connected to a source of sub-atmospheric pressure. By such fluid connection the differential fluid pressures acting on the servo-piston will cause the piston to again return to the lower end of its cylinder.

In order that this cycle of reciprocation or two-way movement of the servo-piston 2 may be again repeated, it will be necessary to reset the reversing valve element 65 in its upper position. To accomplish this the lower end of the casing I3 has reciprocably mounted therein a plunger 88, the lower end of which is arranged to be connected to diaphragm 89 of the previously referred to diaphragm motor D. The lower end of the casing I3 is flared and to the rim of this flared portion is bolted the cup shaped member 98 of the diaphragm motor, the diaphragm 89 being clamped between the peripheral flange of the cup shaped member and the flared portion of the casing. Between the diaphragm and the cup shaped member 98 there is interposed a coiled spring 9I which normally acts to move the diaphragm upwardly and also the plunger 88 which is operatively connected to the center ofv the diaphragm. The upward mover ment of the diaphragm under the action of spring 9| is limited by circular flanged edge of the upper diaphragm clamping cup engaging the flared portion of the valve casing. This upper cup and a similar lower cup clamp the diaphragm to the plunger 88. In order that air cannot be trapped between the diaphragm and.

the flared portion of the casing to prevent the spring from moving the diaphragm, the plunger has an axial passage 92 communicating with the exterior of the plunger by a cross passage 93 positioned at a point close to the diaphragm. Since the plunger 88 extends into the lower end of the bore 83 in which the valve element 65 reciprocates, it is seen that the axial passage 92 will communicate at all times with atmosphere by way of the axial passage I2 through the valve element to the air ports 99. This shouldered upper end of the plunger 88 has mounted thereon a washer 94 and the lower end of the previously referred to spring I9 is arranged to seat on this washer. The spring 9I acting on the lower end of the plunger 88 is stronger than the spring I9 and whenever the spring 9| is released to freely act upon the plunger 88 it will push plunger 88 upwardly and if the reversing valve element 65 is in its lower position, as shown in Figure 7, it can initially act through spring 19, to increase the tension of this spring, until the upper end of the plunger 88 engages the lower end of the'valve element 65. The diaphragmspring 9! will now act directly on the valve'element 65 for a limited intermediary distance of the travel of the plunger. The plunger, with the assistance of the spring I9, will then disengage the ball detent 83 from the upper recess 84 in the side of the rod 88 whereupon the expansion of the spring 79 will complete the resetting of the reversing valve element 65 to its upper position as shown in Figures 4 and 8. The valve element 65 is now positioned for controlling another cycle of reciprocable movement of the servomotor piston when conditions are such that it will again be actuated. The spring 19 is normally pre-lcaded a certain degree when the valve element 85 is in its upper position, as shown in Figure i, and when the valve element 65 is moved downwardly, as shown in Figure '7, the tension is increased, which tension is fur ther supplemented when the plunger 88 is urged upwardly by the spring 9| so at the point Wherein the plunger 88 engages the valve element 65 the tension of the spring 19 has reached a degree almost suiiicient to snap the valve element 65 back to its upper position by overcoming the resistance ofiered by the ball detent 83 and recess 84. Therefore, the spring tension of spring I9 from a preloaded condition is increased by movements of both the servo-piston and the plunger.

The Washer 94, besides serving as a seat for the spring 79, also serves as a movable member for making and breaking the previously referred to master switch M. As already noted, this master switch is provided with two fixed terminals 26 and 21 (Figure 10) which are mounted in suitable insulation in the casing I3 so as to be near the cylindrical wall at the bottom of the valve bore 83. The lower surface of the side of the bottom of the washer 94 carries an annular conducting ring 95 suitably insulated therefrom, shown in detail in Figure 9, and this conducting ring is arranged to contact the two fixed terminals 26 and 2! whenever the washer 94 assumes its position at the bottom of the bore 68, which position will occur whenever the diaphragm motor D is operated by difierential fluid pressure. Whenever the plunger 88 and washer 94 are moved upwardly by spring 9 I, however, the master switch M will be opened, due to. the fact that the conducting ring 95 is disengaged from the terminals 28 and 21.

The diaphragm motor control valve DV, which is employed to control the movement of the diaphragm 89 downwardly against the action of the spring 9|, or to releas the spring to expand to move the plunger 88 upwardly, is shown in detail in Figures 4, 7 and 8. This valve has a casing 98 secured to the bottom of the cupshaped diaphragm motor member 99. The casing is provided with a bore 91 in which is slidable a valve element 98. This valve element 98 is provided with an annular groove 99 which can be arranged to place diametrically positioned ports I00 and IDI in communication with each other, the port 198 communicating with the chamber formed by the diaphragm and the cupshaped member 98 and the port I8I being connected to the previously referred to conduit 22 which is in communication with the tank T. A spring I82 acts on the valve element 98 to normally bias the valve element to the position wherein the groove 99 connects the two ports, this position being determined by means of a pin I83 engaging the rear end wall of a longitudinally extending slot I94 in the valve element, all as best shown in Figures 4 and '7. The valve element 98 is also provided with an axial passage I which is arranged to communicate with a longitudinally extending surface groove I98. The groove and passage both communicate with atmosphere through a port I81 at the rear end of the valve casing and when the.

valve element is moved inwardly to shift the annular groove 99 out of communication with the two ports, the groove I99 will communicate with the port I99 and thus connect the lower chamber of the diaphragm motor with atmosphere and thereby allow the diaphragm, together with the rod 88, to be moved upwardly by the spring 91. Figure 8 shows the valve element 98 moved to its rearward position wherein suction will be cut oil" from the diaphragm motor and the said motor connected with atmosphere.

The valve element 98 is arranged to be shifted 111 rearwardly by the already mentioned manuallyoperated member taking the form of-the pedal P shown in Figure l.

which is arrangedtobe'oonnectedbyarod H2 with a bell crank lever I I3 which provides a connection to a rod ll l arranged to be actuated the pedal. Aspring I lfiacts upon the bell crank lever I I3 to normally bias the pedal to its released position, whiohposition will cause thevalve element 93'to assumeitsopenposition shown in Figures 7 and'8 wherein the diaphragm motor willibe operated by differential fiuidpressure as the result of beingconnected to the tank '1; The pedal P can be pivoted on any desired point, but

as. shown is pivotally mounted by means of a bracket lidtoya ledge I H onthe same bracket I iLby which the reversing valve means isimounted;

togthe support I5;

The reversing valvejmeansis also arranged to have associated therewith the previously referred to shut-off valve SVwhichis actuated by the solenoid 23, in the alreadyv referred to primary circuit. controllable by the speed-responsive device S. The purpose of the-'shut-off valve SV is.- tocontrol the servomotor-F so that the piston thereof will be caused to have a single stroke only fromthe lower end of the cylinder to the upper end, where it will remain untilcertain conditions are fulfilled, as'will be apparent from thedescription of the operation. The-shut oii valve-means valve element.

ciprocable to reset the reversingvalve element. Slidable in the .bore IIBis-avalve-e1ement ilfirin the form of; a plunger;

groove ifiiibso arrangedinthe valve element that when the valve element is at the-extreme righthand position, as. viewed inthe'FigureB and-the solenoid is tie-energized, the groove will allow airtofiow through the passageli-in the same manner. as if the valve element were not present. When the. solenoid :isenergized the valve element will be moved to the leftfroin-the position shown inzFigure 8, to the position shownin Figure 4" wherein thepassage 'ii will beblocked off so that thejlower end'oithe'iiuidmotor cannot be connected'to the source of suction, notwithstanding thereversing-valve element may bein its lowermost position. Ill-017C161- to'place-the lower end of the ser cmotor'in communication with atmosphere when the passage I7 is blocked off by energlzation or the solenoid 23 and a movement of the valve element to the left from the position shownin Figure 8, the valve element is provided with an axial passage I2! and a radial passage.

I22to connect the lower portion of the passage I'Lwith the bore in which the plunger 88 isrw,

ciprocal. To insure free communication with the bore 92 0f this plunger and also with atmosphere,

the upperendoi the plunger is provided with an.

angular passage I23. The inner end of the valve element I I9 is rounded with fiat sides, as shown. The flat sided and rounded end always remains To anextending portion I08: of thelowerend or the casing there ispivotallyi mounted .abell crank lever- I 69; the lower arm of- Which is arranged to engagethe,forwardendot the valve element 98 andthe upper, arm. I Hot This valve element isformed as anextension of the armature of the. solenoid.23: The valve element has an annular engaged ,in the angular passage" I23; which ter? minates into a shallowsurface groove I235 par.- a-llelto the axis of plunger 83, to prevent rotation: of: said element, thus;maintainingv alignment of radial passage I22 and passage ll during sliding movement thereof. The roundedinner end-is arranged to cooperate with theinner angular.- wall I24 of-said passage I23, which innerwall provides a cam surface to push the valve elementt0.:theright from its shut off position, wheneverthe: plunger 88- is shifted upwardly under action of:thecspring 9%. To hold the'valve elementin its shut-off position, there is provided; ayieldabler; detentlfiii which has a very'weakspring-this: detentc-ooperatingwith a recess-I25 in thesur facerof the valve element'so as-to yieldably hold. ittin its shuteoii position.

Operation Referring now to the operation of the disclosed,

improved control system embodying reversing quently, all suction will be shut off from the revalvemeans-ior aservomotor, let it be assumed that the speed-responsive device S is at restand' the personally controlled member'showniasthe.

pedal P is in its normally released postion. Such.

conditions are shown in Figure 1 and as a result thereof it will be seen that the-primary. circuit. will be closed (manual switch 52 -having been previously closed), therebyenergizing thetwo solenoids Hand 24. The reason thatthe primary. ircuit will -be-closed and the two solenoids-are energized is because the master switch M is-in closed position due to the-fact-that with the pedal P in itsfully released position and the .valveDV.

conditioned so thatthe diaphragm motor D.-will.

be operated tomove the plunger 88 downwardly, into the position shown in Figures 4 and 7., The; reversing valve element 65 will bein its 1113136117110?- sition as shown in Figures 4 and8. If thisvalve elementis not already in such upper positiomit canbe; placed there immediately by-depressingthe pedal. P so as to so operate thevalve- DV to; cut-offthe diaphragm motor from the tank Tand place the diaphragm motor in communication with atmosphere. This will release thespring; 91 to'expand andunder its force the plunger-88:

.will be moved upwardly, thus aiding the spring.

19in shifting the reversing valve element 55 to: its upper position. In the event the reversing: valve element shouldbe in the lower position when the primary circuit was energized, the=- servomotor of course would not be operated since suction would be acting on the lower end of its; cylinder and the piston is already at said lower endof said cylinder. Furthermore, with the solenoid 23 energized the shut-01f valve would beeffective to prevent any suction from acting on the'lower end of the cylinder of the'servomotor. Bythe depressing of the pedal and thenreleasing: it in order to cause the reversing valve element to. move to. its upper position, if it should be,in the lower position, it will be further noted that duringthe shifting of the valve element upwardly as a result of the plunger B8v moving upwardly, the master. switch M will be opened and,' conse-.

versing valve means and the servomotor, .due to the fact that the control valve CV willb'ecome. closedas :the primary circuit is broken andthe. solenoid 24 de.-energized..

With the reversing valve element, 65, in its.

upper position, the pedal P released andthe, primary circuit closed, as already assumed, then.

the upper end of the servomotor F will be placed in communication with the tank andthelowell 13 end of the servomotor will be placed in com munication with atmosphere. Consequently there will be a differential fluid pressure acting on the servo-piston 2 and it will be moved upwardly. When the piston 2 of the servomotor reaches the position shown in lines in Figure 1 the bell crank lever 8 will be in a position where the arm 9 thereof begins to engage the plunger 86 and as the piston continues to move upwardly it will press said plunger inwardly against the action of spring 81 until it engages the upper end of the hollow rod 88 to initiate its downward movement and release the spring 81, which is compressed, to quickly shift the reversing valve element to its lower position. This lower position of the reversing valve element will occur when the piston reaches the upper end of the cylinder of the servomotor as shown in dashed lines in Figure 1. The condition of the reversing valve means RV, the shut-off valve SV, the diaphragm motor D and its valve DV will then all be as shown in Figure 7 when the piston has reached the upper end of the cylinder of the servomotor. The piston will now remain at the upper end of the servomotor and cannot return to the lower end of the cylinder. The reason for this isthat the shut-off valve SV is in closed position, due to the fact that the primary circuit is still closed and the solenoid 23 energized. Thus with the shut-off valve SV closed, it makes no difierence that the control valve CV is still in open position due to the energization of the solenoid 24.

The movement of the piston from the lower end to the upper end of the cylinder of the servomotor can be employed to control any desired mechanism. Thus, for example, if the system were employed in controlling the changing of gear ratios of an automotive transmission, this movement of the piston to its upper position could be employed to disengage the friction clutch associated with the transmission and hold it to be held disengaged so that a gear ratio could be established manually by moving a gear-shift lever. With the spring l1 considered as a clutch re-engaging spring, such will be energized when the piston reaches the upper end of its cylinder. When this position of the piston is reached, the reversing valve element 65 will be moved to its lower position as already indicated. Both sides of the piston will then be connected to atmosphere, notwithstanding the closed condition of shut-off valve SV, as passages i2] and I22 in said valve are in communication with the bottom of the piston cylinder. Thus, to prevent a return of the piston by the spring I l and thereby hold the clutch disengaged, any suitable means could be employed. If the spring I1 is not employed in the mechanism actuated by the piston when moved to the upper end of its cylinder, as would be the case when gear shifting only was to be accomplished, then of course the piston would remain at its upper end and no holding means would be necessary.

If the pedal P should now be depressed and there should be provided means for holding the piston from returning to its lower position in the cylinder under the action of the spring ll, such depressing of the pedal will release the holding means and the spring H can be efiective to move the piston to the lower end of the cylinder, thus accommodating re-engagement of the clutch if it is considered the clutch is the mechanism actuated to disengaged position by the movement of the piston to the upper end of the cylinder.

The depressing of the pedal will also cause the diaphragm motor D to be disconnected from the tank T and the spring 9| will be effective to push the plunger 88 upwardly, thereby opening the .master switch M in the primary circuit. The

movement of the plunger upwardly will also open the shut-01f valve SV due to the action of the cam surface l2| acting on the rounded end of the valve element H9. The shifting of the plunger 88 upwardly will reset the reversing valve element to its upper position with the aid of spring 19 and during this resetting the spring [1' will be effective in moving the piston of the servomotor to its bottom position so that the valve element will be free to be reset. When the reversing valve element 65 is reset to its upper position it will not, however, cause the upper end of the cylinder to be connected to the tank T, notwithstanding that this position of the reversing valve element connects the conduit [9 with the conduit 20. Initial upward movement of the plunger 88 caused the master switch M to be opened and since this breaks the primary circuit, there will be a de-energizing of the solenoid 24 and, consequently, the control valve CV will be closed, thus insuring that the tank T will not communicate with the conduit l9.

If there should be no holding means for the piston to maintain it in its upper position, then of course the spring ll will return the piston to the bottom of the cylinder. When the pedal P is depressed under such conditions, the reversing valve element 65 will be reset in its upper posi tion. If the spring l1 should not be present, then of course the depressing of the pedal P will not result in any resetting of the reversing valve element 65 to its upper position because this resetting is prevented by the fact that the piston 2 of the servomotor will remain in its upper posi tion and thereby hold the reversing valve element in its lower position. The depressing of the pedal P will also not have any effect in connecting the tank T to the lower end of the power cylinder so as to cause a downward movement of the piston. It will be noted that as soon as the plunger 88 is moved upwardly as a result of the depressing of the pedal P and a connecting of the diaphragm motor D to the tank, the master switch M will be opened and thus the primary circuit will be broken. Consequently solenoids 23 and 24 will be de-energized and the de-energizing of solenoid 24 will immediately cause the control valve CV to be closed and thus, notwithstanding the fact that the upward movement of the plunger 88 willopen shut-oil valve SV,there nevertheless can be no fluid connection between the lower end of the servomotor and the tank, due to the prior closing of the control valve CV.

If the pedal P should be an accelerator pedal associated with the engine of a motor vehicle, the derpressing of such pedal will speed up the engine and with the vehicle in gear said vehicle will move forwardly. As the vehicle moves, the speed-responsive device 5 will be operated and the centrifuge members moved outwardly so as to open the primary circuit and close the secondary circuit, a condition shown in Figure 6. With the secondary contact 38 now connected to ground by the movable switch element 4| of the speedresponsive device, it will be possible to close the secondary circuit Whenever the master switch M is closed. This can be accomplished by merely releasing the pedal P again. Upon full release of the pedal the diaphragm motor will be connected to the tank and thereby caused to be 1E2 operated; which .will pull theadiaphragmt edownward'lyso thatethermastenswitch:M;will.beclosed..: Upon closingiof; the.masterzswitchzandzthe secondary. circuit. the-:solenoid .124 will be energized;

thereby: op,ening:the.; control valve CV which .will:

themconnectrthe tankzto; the conduit l9.

With the conduit: i 9.; connectedto the tank 1T,

then if;the,.piston ;-.of.'the: servomotor is at the bot tion. Ittwill remain inthisopen position since the.;solenoid:2:3: isgdeenergized, not being in. the

secondary circuit; With the upper: end-of the senvoecylinderviiowz connected; to; the. tank and the lOWlBlZBlldiOf theiseryo-cylinder in communication; with atmosphere; differential fluid pressure; will be: efiective on. the: piston. and 001156?- quently the piston willbetmovedtozitsi upper position.w Asr the:p iston; reaches itsupper position thegreversinggvalveelement 65 will beioperated. by thegarmziliactuated by.-th'e pistonzaand beshiited to. the: lowergposition; in :.the;manner, already described: This .will' immediately" reverse the; di-

rection; of the.- differential. fijuid; pressure acting onzthe: piston:; 2; and: consequently -the;piston of the; servomotor. will abe moved back .:to its lower.

position... Thus-there. will bega complete hackand;

forthor 'reci-procablemovement;of the piston ,2.- Wherri the piston; of: the. servomotor passes through .areciprocablemovement, it will remain atthebottommf', itsgcylinder during .a subsequent depressing vofrthe pedal .P This. subsequent depressing f of i the; pedal, however, will. disconnect thezdiaphragm motonD from thetanl:- T and connect-it .withatmosphere. As a result, spring ,9!

with 1 the aid :of spring; l9rwill again function-toshift the reversin valve element to: its upper position',therehy;v resetting the valve .for another reciprocation of. the piston of theservomoton- As lenses-the pedal remains released after a piston movement oris.againidepressed, there will beno movementof the piston of the seryomoton I-Iowever,-when the pedal is released after a depressing movement there: will then occur another complete reciprocation-of:thepiston of-the servomotor and the; cycle .5 of .1 operations. of the. reversing valve; means will ..occur: in a. manner already described.

The reciprocation ;of the; piston of the; servomotor will always :occurlwhenever'the secondary'circuittis energized-wandithe pedal P is depressed and then released;

Underconditions: wherein spring 17'. is eliminated,- the piston-10f the servomotor willbe at the upper end ofits cylinderwhen the primarycircuit:is broken and the secondary circuit is closed' by: the.speedqesponsive device Si Also under such conditionsthe reversing valve element 65 will still be held in itslower position as shown in Figure 7. The valve element ll9'of the shut-oii valveSVwill be in-its-open position and'thus there-will b'e:a.fluid connection with the lower end-.ofithe servomotor. The'reason that the valve element ;oi j the shut-off 'valveSV is open is -be-- causegpriorrto. the release of the pedal P the upwardjimovement'.ofytherplunger- 88- under the -ac-- tionzof "the spri'ng m I l of the diaphragm motor -D agsoaeoo;

f6 hadicausedzanzopeningzof thewalveaelementiunder: thergcammingraction.of'the angular surfaceel 24; it:

beingnotedthat the valve element could no longer;

beamaintained closedibecausethe: solenoid 2.3 fiber? came: dei-energized and remainedtde-energized upon; the opening of .the primarycircuitr. Thus;

ifrthereishouldbesa release of: the. pedall. under. the ,conditionsgsetzforth; adiffe'rential fiuid;pres-.-- sure; willbercaused to:act' downward upon -the.2pis-' ton 2- of: the servomotor and said: piston a will. be" moved from'its .upper-rendito its lowerend where. it 'will .remain until .the; pedal is again depressed: andreleasedii Withxthe pistonofithe'. servomotor nowvatether lower endof its cylinder and the: secondaryrcirecuitqistill .1 energized, the piston .and'x theyreversingr valve. means will .bezin' such a condition that'tdee pressing and releasing; of. the: pedalEP willresult in-a; complete abackandziorth .movementlor. reciprrocation ofthe servoepiston 2fin' arm-annen'which;

has, already been described: When" the zpedal P isrdepressedraiterrthe piston has reached the-hots tom of thecylinder; therewill'first occurc'alee setting of the 'reversingvalveelement 65: This-is:

.; brought. about by: the: connectingof the dia':

phragm motor-D to-atmosphere as thespedal is de:- pressed and'the: valve =DV movedftorits rightihand" position has shown ;in Figure: 8; Thepspringfll is: now: free-to expand; and. the: plunger 88 willibe:

. moved upwardly,- opening/the mastenswit'chzM' and thereby -de;-energizing-.: the; solenoid; 2'4 and: closing; the .control walve .CV; The continuediupward movement of the plunger 88 willithenirea sultin the reversingvalve*e1ement'l65 assuming 3 its upper-position: Withthe'reversingvalverele ment 1 65 reset :it is then obvious: that ,when ..thes.

pedal is released" thesservomotorwill beaoperated': andthe piston :thereof willmove from: the bot-' tom'position; to:.its.upper position, wherein the; arm". 9': will again cause :thereversing valve; ele-. merrt. 652to move to' its:.lower position and thus; reverse the fluid: connections of the servomotor"- with:the-tanlc-T andatmosphere; Asaresult of this i'eversa'l, the piston 2 "will1bejmovedrby=dif= ierentia'l fluid-. pressure to its bottom position,v thereby completing the reciprocative" movement: 'It1is :seen from the; foregoing description of the operation oftmy novel reversing'valvejmeans. and' control :means that upon closing of?the secondary circuit; the .pistoniof the servomotorrcanbe'caused L toi-have agback and forth movemcntzupon eachr depressingandreleasing of the. pedal-1R Ifthe spring. I i or itsequivalent should he.- elTective on: the piston; and the-'- secondary circuit is 1 closed,

v then-.asrthe pedalP'fis depressed the piston will'be:

movedftothe bottom of itscylindenundertheaction .of the spring l'i'andthe reversing valve element will be resetso that the release of'the pedal iwillresult in a reciprocation of the piston. of theservomotor. Under conditions wherein the spring I? or itsequivalent isnot efifective-on the piston; then thepiston will be at the upperend ofthe cylinder when the pedal? is-depressed after initial closing of the secondary circuit. The

- releasing of the pedal under these conditions will not result inthe reciprocation of thepiston as there has not been'any resetting of-the reversing valve element; that is, amovement from its lower position to its upper position, because-such-re setting'is prevented by the position of'theservopiston at=the upper end of its cylinder.- A release of'thepedal, however, will resultin the "tank. 'T1 beingconnected to the-lower end of the cylinder of the servomotor" and'thus cause the piston to move-to the-"bottom position; When; this concli+ tion exists, then there will be a resetting of the reversing valve element by depressing pedal P so that the reciprocation of the piston can take place upon the next release of the pedal P. It is, therefore, seen that with the spring ll eliminated there must first be a depressing and releasing of the pedal P before the control mechanism is con ditioned so that each subsequent depressing and releasing of the pedal brings about the reciprocation of the piston of the servomotor.

If the speed-responsive device S should again return to rest or to such a condition wherein the primary contact is connected to ground and the pedal should be placed or already is placed in released condition, then the cycle of reciprocation will be broken. What will occur, however, will be the movement of the piston 2 of the sercornotor from its bottom position to its upper position in the cylinder. The closing of the primary circuit with the pedal released will result in both solenoids 23 and 24 being energized in the manner already described. The energization of the solenoid 23 will therefore close the shut-oil valve SV, thereby preventing the tank T from being connected to the lower end of the cylinder of the servomotor. When the piston of the servomotor reaches its upper position it will remain there as long as the pedal is not depressed. If the spring H or equivalent is to be effective and there is provided some type of holding means therefor, the piston cannot return. If the spring H is not present, then the closed condition of the shut-off valve [SV will insure that the piston will remain at its upper position, notwithstanding the reversing valve element is shifted to its lower position. Of course if no holding means is provided for the spring ll, then even with the pedal released the piston will return to the bottom of the cylinder under the action of the spring as both ends of the servo-cylinder will be connected to atmosphere. If holding means is provided for the spring ll, then of course the piston can be actuated to return to the bottom of the cylinder by depressing the pedal P. If the secondary circuit is again closed, then the reciprocation of the piston can again be brought about in a manner already described in detail.

From the foregoing description of the operation of the control system embodying the reversing valve means RV, it is seen that there is provided a control means for a servomotor by which the piston thereof can be caused to move from one end of its cylinder to the other end and remain in such position and upon the occurring of other conditions, which include the closing of the secondary circuit, the piston of the servomotor can be caused to have a complete reciprocation; that is, a movement from one end of the cylinder to the other end and an automatic return movement, all under the action of differential fluid pressure.

It is also seen from the foregoing description that the control system embodying the reversing valve means RV is very well adapted for controlling the changing of gear ratios of a change-speed transmission of a vehicle. The servomotor can be employed to disengage the vehicle friction clutch and it can also be employed to accomplish the changing of gear ratios. For example, the upward movement of the piston can accomplish the disengagement of the friction clutch and the downward movement of the piston can be employed to accomplish the shifting of the transmission elements to establish the different speed drives. When employed to both disengage a friction clutch and change the gear ratio or drive of a transmission, the re-engaging movement of the clutch can be slowed down by any suitable retarding means so that the shifting of the transmission can be accomplished by the fast downward movement of the piston before there is any actual friction clutch re-engagernent. One example of a particular use of the control system embodying the reversing valve means RV woul be in the operating of a pre-selective gear shifting mechanism such as that disclosed in my U. S. Patent No. 2,126,032, issued August 9, 1938, for Motor Vehicle Transmission Control. In such a pre-selective control mechanism, neutralization of an active gear ratio is accomplished by a movement of a reciprocal member in one direction and establishment of a pre-selected gear ratio is accomplished by the return movement of said member. Thus it is obvious that the servo-piston 2 controlled by the reversing valve means RV and its control means could be employed to do the neutralizing of an active gear ratio and the establishing of a pre-selected gear ratio when reciprocal movement takes place. The engine friction clutch could also be disengaged and controlled to re-engage during the reciprocable movement of the piston 2 if such were desired.

In Figure 11 there is disclosed a slightly modified means for resetting the reversing valve element of the reversing valve means RV, the modifled structure disclosing means for causingthe resetting to be accomplished directly by manual force through the pedal P. The modified reversing valve means is indicated by the letters RV and the structure shown differs from the previously described structure primarily in the elimination of the diaphragm motor D and its control valve CV. All the structure of the reversin valve means RV and theshut-off valve SV', which is identical to that already described, is indicated by like reference numerals. The plunger 88 is replaced by a plunger 88. The lower end of this plunger is arranged to be operated by an arm I I0 pivoted on a pin I21. Also pivoted on this pin is an arm Hi to which the rod H2 actuated by the pedal P is operably connected. The arms H0 and III are operatively connected together by a torsional spring I28 which is of sufficient strength to cause a movement of the two arms in unison when the pedal is depressed to thereby move the plunger 88' upwardly and thus cause a resetting of the reversing valve element. The upward movement of plunger 88 also will open the shut-off valve SV by the cam surface I24 as shown in Figure 11. When the plunger 88 is moved upwardly to the limit of its movement, the spring [28 can yield to accommodate additional movement of the pedal P as desired. When the pedal P is fully released the plunger 88' will be released to return to itslower position which will close the master switch M in the same manner that the master switch M was closed by the operation of the diaphragm motor D in the previously described reversing valve means RV. The operation of the modified reversing valve means RV with the direct mechanical linkage means for manually resetting the valve is identically the same as the operation of the reversing valve means RV already described in detail. Each time that the pedal is depressed the plunger 88' will be moved upwardly to reset the reversing valve element if such is conditioned to be reset by the position of the piston of the servomotor F.

Having now illustrated and described different 1 9 embodiments'of my invention, I desire-it to be understood'that my invention is not to be limited, in the broader aspects thereof, to the-specific forms, combinations andjarrangements of structure herein shown and described for illustrative purposes, except in so far as such limitations are specified in'the appended claims.

I claim as my invention:

1; In combination with a fluid servomotor havinga reciprocableelement and a source. of fluid pressure. therefor different from atmosphere, a reversing valve means comprising. a. valve. element movable to two operative positions for alternately connecting the source with opposite sides of the motor reciprocable element, means for. placing said valve element in one of its operative. positions toconnect'one side of the motor element tothe source andthereby cause said motor element tovmove from. a firstposition to a second position, means operable by themotor elementwhen in .the second positionfor. place ing.- .said valve element in its other operative position, to therebyconnect the. other. sidev of the motor with-the source and cause the motor elementto return to itssaidflrst position, .a reciprocable member for resetting the valve. element, manually-controlled means forcausing the member to reset the. valve. element, a control valve means. between the sourceand the reversing valve-means, electrical means including an electricalcircuit' for controlling the controkvalve, and5.means--operab1ef by'the. movement of the reciprocable-member when resetting the valve element' for controlling the electrical circuit to causeaclosingpf the :control valve means.

2? In combination with a fluidservomotorhaving:a"r.reciprocable elementiand a; source of. fluid pressure therefor different .from atmosphere, a reversing valve. means comprising a. valve element .movable: to.v two operative positions for alterna.telyconnecting the source with opposite sides of the motor reciprocable element, means forrplacin-gsaid-valve-element in one of its operative'spositions-to connect one :side of the motor element to the-source and thereby cause said motor-:relement to:move from a" first position to assecondi' position, means-operable by the motor element whentirr the :sec'ondvposition for placing saidzvalver element .irrits other operative position tox-th'ereby: connect the other sideiofthe motor with-the source and. cause. themotor element" to return to its said' first V position; a reciprocable member'ior resetting' the valve element, manually-controlled means for causing the member to reset'thevalve-element; acontrol valve means betweenthe source and the reversing valve means; a solenoidenergizable for opening the control-valve, an electrical circuit includin a source-of'electrical energy and-a switch for the solenoid, and" means operable .by'the movement of the reciprocable" member when resetting the valve element for openingthe switch'to de-energize thesolenoid andthus close the control valve means:

3." In' combination with a fluid servomotor havingia reciprocable element'and a source of fluid pressure therefor difierent from atmosphere, a reversing valve, means comprising a valve element movable to two; operative positions for alternately.connectingthe source with opposite sides of the motor reciprocable element, means for".placing said; valve element in. one of the operative positions tdconnectone side. of the motorelementto the source and thereby cause said motor elementto move from a-first'position to a second position, means operable by the motor element when in the second position-for placing-said valve element in itsother operative position to thereby connect the-other side -of'the motor with the source and causethe motor element to return'to its first position, means? for resetting-said valve elementin its first position, valve means for cutting off communication ofthe source with the reversing valve meansl a solenoidfor maintaining the last-named valve means open, an electrical circuit for the solenoid including a speed-responsively controlled-switch and a second-switch, and means operable bythe. resetting means for Opening" the second swi tch'.

4. Incombination with a fluid servo-motorhaving a'reciprocable element and a source of fluid pressuretherefor difiere-nt fro-m atmosphere, reversing valve means interposed between said source -and said motor and-controllable bythc i'eciprocable element for movement to a plurality of operative positions; thevalve meanscon'necting the source with the motor sothat the re-'- ciprocable element will be caused'to move from afirst position to a second p'ositionand to have a return movement to itssaid first position, said valve means-being conditioned by. movement of said reciprocable element to one of the .operative positions, and combined speed-responsively controlled means and personally-operable means interposedv between said source-and'said reversing valve means for overruling said valvemeans. thereby'causingthe motor element-to remain at its said second position despite theconditioning of the reversing valvemeansunder-thecontrol of the reciprocable element to normally cause the motor element to be returnedto the first of its said positions.

5. In combination with a fluid servomotorhaving a. reciprocable element and" a source "of "fluid pressure therefor different from atmosphere, reversing valve means interposed between the source and the motor, meansincludingth re versing valve means for connectingthe source withthe motor-to causemovementofthe-reciprocable element from a first position to' a second position, means for operating the revers= ing valve element by the'reciprocable element when said element assumes itssaidseoond posi:- tion, said last-mentioned means being effective to condition said reversing valve toconnect said motor to the source for causing ,the-reciprocable element to return to. its first. position; a per.- sonally-operable member, additional .valvemeans controlled by the personally-operable. member and operativelyinterposedIbetweensaidreversing valve means and said source for controllingthe connection of the reversing. valve meanswith the source, andv means. including. means: also. controlled by the personally-operable memberand interposed between the reversing, valvemeans and themotor for causing the..motor.elementto remain atthe second position despitethe conditioning of. the reversing, valve-.me ans by, the

'motorelement to cause the motor. elementto. be

returned to its first position.

6. In combination .with afluid serv omotorhaving a reciprocable element and .a source. of. fluid pressure therefor difierent from atmosphere, a reversing. valve. means. comprising avalve element movable to firstand secondoperativepositions for alternately; connectingthe source. .with opposite sides of the movable.- element of; the motor, means for placingsaid valverelementin its firstposition to connect one side of the movoperable power means for opening said shut-off valve element.

7. In combination with a fluid servomotor having a reciprocable element and a source of fluid pressure therefor different from atmosphere, reversing valve means operatively interposed between the source and the motor and controllable by the reciprocable element for movement to first and second operative positions to connect the source with the motor for causing movement of the reciprocable element from a first position to a second position and through a return movement to the first position, shut-01f valve means between the reversing valve means and the motor, said shut-off valve means when closed preventing connection of the source with the motor for causing movement of the motor element to the second position, a speed-responsive device operable to a first controlling position to cause closure of the shut-off valve means and to a second controlling position to accommodate opening of the shut-off valve means, and personally-operable means for opening the shut-off valve means when the speed-responsive device is in said second position.

8. In combination with a fluid servomotor having a reciprocable element and a source of fluid pressure therefor different from atmosphere, reversing valve means comprising a valve element for alternately connecting the source with opposite sides of the movable element of the motor, means for actuating said valve element to connect one side of the movable element with the source causing the element to move from a first position to a second position, means controlled by the element when in its second position for actuating the valve element to connect the other side of themotor element to the source, a shut-off valve element between the reversing valve element and the said other side of the motor element, a speedresponsive device, a solenoid energizable for causing said shut-oil valve element to be closed, an electrical circuit for the solenoid, a switch in the circuit, and means for closing and opening the switch by operation of the speed-responsive device.

r 9.- In combination with the accelerator pedal of an engine and a fluid servomotor having a reciprocable element and a source of fluid pressure therefor different from atmosphere, reversing valve means operatively interposed between the source and the motor and movable to a first operative position and to a second operative position, means including the reversing valve means when in its first position for connecting the source with the motor to move the reciprocable element from a first position to a second position, the reversing valve means being actuatable to its second position for connecting the source with the motor to :return the reciprocable element from its first position to its second position, means operatively connecting the reversing valve means to the reciprocable element, said reversing valve means being actuated to its second position when the reciprocable element assumes its second position for returning the reciprocable element to its first position, shut-off valve means operatively interposed between the reversing valve means and the motor for actuation to a closed position to prevent the motor element from being moved from its second position despite the conditioning of the reversing valve means to its second position by the motor element, speed-responsive means for selectively controlling the actuation of the shutoif valve means to its said closed position and to an opened position wherein return of the motor element is accommodated, and means controlled by the accelerator pedal for actuating the shutoff valve means to open position when such actuation is accommodated by the speed-responsive means.

10. In combination with a fluid servomotor having a reciprocable element and a source of fluid pressure therefor different from atmosphere, a reversing valve means comprising a valve element for selective actuation to a first position and to a second position for connecting the source to opposite sides of the movable element of the motor, means for placing said valve element in its first position to connect one side of the movable element with the source to move the element from one position to a second position, means controlled by the fluid motor element when in its second position to condition the valve element for connecting the other side of the motor element to the source, a shut-oil valve element operatively interposed between the reversing valve element and the other side of the motor element, speed-responsively controlled means for selectively actuating said shut-oil? valve element to a first closed position for preventing connection of the other side of said other element to said source and to a second opened position at which such connection is accommodated, and personally-operable means for actuating the shut-off valve element to its open position and for resetting the reversing valve element to its first-named position.

11. In combination with a fluid servomotor having a reciprocable element and a source of fluid pressure therefor different from atmosphere, a reversing valve means comprising a valve element operable to two operative positions for selectively connecting the source with opposite sides of the movable element of the motor, means for placing said valve element in a first of its positions to connect one side of the movable element with the source for effecting movement of the element from a first position to a second position, means controlled by the fiuid motor element when the same: is in its second position for conditioning the valve element to normallyconnect the other side of the motor element'to the source, shut-off valve means operatively interposed between the reversing valve element and said other side of the motor element, said shutoif valve means having an open position and a closed position at which closed position said source is prevented from communicating with said other side of the motor element while communication of said other side with atmosphere is accommodated, means for closing the shut-off valve means, spring means acting on said motor element to return it from its second position to its first position, and personally-operable means for actuating said shut-oil valve means to open position and for resetting the valve element of the reversing valve means in its said first position wherein said valve element is efi'ective to connect said-i first side. of the fiuidmotor element to the.

source:

. 1 2. In: combination. with a. fluid servomoto'rfl having, a. reciprocable. element and a source, of; fluidpressure. therefor difierent from atmosphere-,-. a reversing valve means. comprising, a valve-elementoperable to first and second opera! side-of the movable element-with the source. for. causing. thev elementto :move from a first position-to. as second s position, meanslcontrolled bythevflui-dlmotor element when in its second. position fon actuating the valve element to its sec.- ond operative position to accommodate the. con.- nectionof the' other side ofthe motor element to thezsource, shut-off valve-fmeans operatively, interposed between i the reversing valve element. andsaid-othensideof said motorelement, said shut-eon? valve. means being operable. tov an.

opened .positionand to. a closed position at which closed ,position communication .ofithe, sourcewith the :said; other side. of. the motor element is. preventedtandsaid other side. isplaced in com-.- municationwith the. atmosphere, spring. means. acting; on-the. motor element to-return it from its said seconds-position tov its said first position whenethe shut-off valvemeans is-.in.closed. position,-..speederesponsively controlled meansfor. seleetively actuating, the shut-off valvemeans to either: of its; positions; and personally-operable. meansoperable iii-cooperation with-said speed! responsively controlled means for. actuating the shuts-01f valve means-to open. position and. forresetting the valve elementof the. reversing valve means to its. first position.

13. In; combination with a fluid. servomotor having; a reciprocableelement and a source of fluid.fpressure-.. therefor difiering from. atmosphere,- a: reversingvalve means comprising are.- oi-procable valve element movable to..first. and second operative positions for selectively connecting. the source with opposite: sides. of' the movable. element of. the motor, means for yieldably holding. the valve. element in each of. its two operative positions, means for moving the valveelementtfrom' its first'operative position to its:secondoperative position by movement ofithe 1 motor element as themotor element is actuat'edby'fiuidpressure froma first positionto-a second "positionf the movement of saidvalve elementto its second position reversing-the connections'of the source with said motor and causing fluid pressure in-saidmotor to move the r'not'or element-bac-k'to its--=first position, aplunger, a spring operatively interposed between one end of theap-lunger and the valve element; said: end of:'tlie plunger being normally spacedlfrom: the valve. element to accommodate compressionw of the; springtas the ValVGTEIGmGHtQ is" moved to r its saidillsecond'operativer position by the. motor olement/1 and; toprevent; contact of thelvalveiele.- ment .andizthe plunger end; and; personally operable-1 means: for movingthe plunger: toward-the valve elementto further'compress the spring and then subsequently engage the valve element to free; the valve element'from :the associatedyieldableholding; means, said valve element being then-unovedby -the; stored energy'of the spring to itsesaid first position.

14. In. combination with a: fluid servomortor having a: reci-procable elementcap'able of primary movementnfrom a first. position to asecond position and. return movementto said. firstposie 24 tion and a source of fiuidpressure therefor ditferent from atmosphere, a reversingvalvemeans comprising a reciprocable-rvalve element. movable toalternate firstand. second operative positions for alternately; connecting the source with opposite sides of the movable. element of the. motor, means for yieldablyretaining. the valve. element in eachof itstwo operativepositions,

means for moving the valve element from first :operative position to it s.secondoperativeporsition as a consequence of 1 primary movementiofq themotor element under theinfiuence of .fluid.

spring; as-the valveelement is.. movedltoitsssaido second: operative position by? the, motor elementand; without contact I of the valve element. and.

the plunger end, meansfor moving therplungen.

toward the valve elementto furthercompress theh spring; a and then subsequently, engage. thei valves element .to vfree; the valve elementefrom. the ase sooiated yielda'ole retaining means. said. valve,

elementthen being movedlby the stored energy, of .the spring tov its; said ,first operativepositiom,.a. solenoid-controlled valve operatively interposed between the sourc'e. and the reversing. valve, an.

electrical. circuit. for. the, solenoid including, a switch, the valve being open when the, switch is closed-and the solenoidenergized,v andmeans: ion: opening the switch upon movement of the plungertoward the reversing, valve.- element to further. compress thespring, and. prior; m. the plunger engaging said; valve: element.

15.- In combination with a fluidv servomoton having a :reciprocable elementcapable of primary,

movement from a .first position to v a 86001111 13031: tion .andof return movement to said first hposie tion-and a sourcerof fluidpressuretherefon difI- ferenttfromatmosphere reversing; valve. means interposed between rthersource andlthe; motonfor. movementto a first motor operative .positionzand to a. :second motor operative. position, saidrevers-i ing', valve: means. being; controllable-.- by the resciprocable-element for connecting: the source with the motortocause both primary and returnmovee ment otsaidreciprocable element, .shuteofiyvalve means :operatively interposedbetweenIthereverse ing valve means and ,themotor, ,saidshutwfitvalve. means being aotuatable:toclosed position fonpreventing the. return. movement of. the motor! element, control valve means operatively interposed between the source and. thereversingivalve means and actuatable to open position .for. establishing a communication therebetween, a speed-respone sivedevice, personally-operable'meansz:and means cooperatively controlled by; the. speed-responsive device. and, said personally-operable means? for selectively-causing actuationlof said shut-soft valve means. andlsaid control-valve. meansrto-difierent operative positions, including, a. first position in which. the. shut-off. valve, means t closed and the control: valve meansiisoopen, t and. a; second positiomatswhich only the control valve meansatmosphere Ior actuating said fluid motor, reversing valve means interposed between said source and the motor for movement to a first operative position and to a second operative position, said reversing valve means being controllable by the reciprocable element for connecting the source with the motor to cause both primary and reverse movement of said reciprocable element, shut-ofi valve means operatively interposed between the reversing valve means of the motor, valve means being actuatable to a closed position for preventing the return movement of the motor element, control valve means operatively interposed between the source and the reversing valve means and actuatable to an opened position for establishing communication therebetween, a speed-responsive device, personallyoperable means, solenoids for closing the shutofi valve means and opening the control valve means when energized, an electrical circuit ineluding both solenoids, a second circuit including the solenoid for the control valve means, means actuated by the speed-responsive device for selectively closing said circuits, and switch means operable by the personally-operable means for closing and opening the circuits.

17. In combination with a fluid servomotor having a reciprocable element capable of primary movement from a first position to a second position and of return movement to said first position and a source of fluid pressure different from atmosphere for actuating said fluid motor, reversing valve means interposed between the source and the motor for movement to a first operative position and to a second operative position, said reversing valve means being controllable by the reciprocable element for connecting the source with the motor to cause both primary and reverse movement of said reciprocable element, shut-off valve means operatively interposed between the reversing valve means and the motor, said shutoff valve means being actuatable to closed position for preventing the return movement of the motor element, control valve means operatively interposed between the source and the reversing valve means'and actuatable to opened position for establishing communication therebetween, a speed-responsive device, a personally-operable means, solenoids for closing the shut-off valve means and opening the control valve means when energized, an electrical circuit including both solenoids, a second circuit including the solenoid for the control valve means, means actuated by the speed-responsive device for selectively closing the circuits, switch means operable by the personally-operable means for closing and opening the circuits, and means also operable by the personally-operable means after said switch means has been actuated to opened position for resetting the reversing valve means following a reciprocable movement of the motor element through both its primary movement and return movement.

18. In combination with a fluid servomotor having a reciprocable element capable of primary movement from a first position to a second position and return movement to said first position and a source of fluid pressure different from atmosphere for actuating said fluid motor, a reversing valve means including a valve element having a first operative position and a second operative position for alternately connecting the source with opposite sides of the movable element of the motor, means controlled by the fluid motor element when the valve element is in its first operative position for causing primary motor element movement, said last-mentioned. means actuating the valve element to its second operative position for causing reverse movement of the motor element, personally-operable means for re-setting the valve element to its first operative position to condition the valve for an ensuing primary movement of the motor element, and means for causing said motor element to have a reverse movement only after its initial primary movement despite the prior conditioning of the valve element to its first operative position by operation of the personally-operable means.

19. In combination with a fluid servomotor and a source of fluid pressure different from atmosphere for actuating said fluid motor, valve means having a first operative position and a second operative position for alternately connecting the source with opposite sides of the movable element of the motor, means controlled by the fluid motor element when the valve element is in its first operative position for causing primary movement of said reciprocable element, said last-mentioned means being operable to condition the valve means for causing return movement of the reciprocable element, pedally conrolled means for causing the valve means to be conditioned for effecting a second reciprocation, and means including a shut-off valve interposed between said valve means and said motor and a speed-responsive device for controlling said shutoff valve for preventing a second primary movement of the motor element despite the conditioning of the valve means for such primary movement after the motor element has completed its reverse movement.

GLENN T. RANDOL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 203,801 Waring May 14, 1878 1,230,156 Geraghty June 19, 1917 1,620,527 Emmet Mar. 8, 1927 1,905,133 Bishop Apr. 25, 1933 1,931,452 Wheeler Oct. 17, 1933 1,994,835 Sanford Mar. 19, 1935 2,020,847 Mitereff Nov. 12, 1935 2,159,879 Dewandre May 23, 1939 2,161,150 Flygare June 6, 1939 2,227,657 Linsley Jan, 7, 1941 2,373,167 Cherry Apr. 10, 1945 

